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- Title
High Solids Hydroxy‐TEMPO Mediated Radical Semibatch Emulsion Polymerization of Styrene.
- Authors
González‐Blanco, Roberto; Jiménez‐Reyes, Nelson; Cunningham, Michael F.; Saldívar‐Guerra, Enrique
- Abstract
Stable polystyrene latexes having controlled molecular weight distribution (MWD) with solids contents up to 40 wt% are obtained using potassium persulfate as initiator with the nitroxides 4‐hydroxy‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl (hydroxy‐TEMPO) and 4‐amino‐2,2,6,6‐tetramethylpiperidine‐N‐oxyl (amino‐TEMPO). Using different concentrations of styrene (St) in the nucleation step, it is possible to create colloidal dispersions with particle size ranging from ≈57 to ≈390 nm, conversions up to ≈96%, nitroxide efficiencies (NEff) up to ≈0.76, and number average molecular weight (Mn) ranging from ≈10 000 to ≈85 000 g mol−1. The effect of the monomer feed rate in the semibatch step is also studied. These polymerizations do not require a separate macroinitiator synthesis, since this is formed in situ during the heating ramp. A mathematical model is used to compare the mechanistic understanding of the system with the experimental results.
- Subjects
EMULSION polymerization; STYRENE; MOLECULAR weights; MONOMERS; SOLIDS; NITROXIDES; NITROXYL
- Publication
Macromolecular Reaction Engineering, 2021, Vol 15, Issue 2, p1
- ISSN
1862-832X
- Publication type
Article
- DOI
10.1002/mren.202000054